Slip on groove coupling with multiple sealing gasket

ABSTRACT

Couplings and gaskets are disclosed. Couplings may include an upper housing, a lower housing, at least one fastening device coupling the upper housing to the lower housing, and a gasket positioned within the upper and lower housings, the gasket including two primary seals and a rib protruding from an inner surface of the gasket and between the two primary seals.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/019,182, filed Sep. 5, 2013, which issued into U.S. Pat. No.9,239,123, on Jan. 19, 2016, which is a continuation of U.S. applicationSer. No. 13/554,721, filed Jul. 20, 2012, which issued into U.S. Pat.No. 8,550,502, on Oct. 8, 2013, which is a continuation of U.S.application Ser. No. 12/490,113, filed Jun. 23, 2009, which issued intoU.S. Pat. No. 8,282,136, on Oct. 9, 2012, which claimed the benefit ofU.S. Provisional Application No. 61/133,300, filed Jun. 30, 2008, all ofwhich are hereby specifically incorporated by reference herein in theirentireties.

BACKGROUND

1. Field of the Invention

The invention is directed to coupling devices used to join sections ofpipe and methods of their use and, in particularly, methods and systemsof coupling devices that are installable in one unit withoutdisassembly.

2. Background of the Invention

A common type of pipe coupling device used to join two pipes employs ahousing consisting of two half-circular elements joined together withbolts at either end. Usually the housing is used to secure two lengthsof pipe together. In order to prevent leaking between the two pipes, agasket is usually secured around the seam created at the junction of thetwo pipes. The two halves of the housing surround the gasket and pressthe gasket around the seam. FIG. 1 shows a basic coupling device 100.Coupling device 100 includes an upper housing 105 and a lower housing106. Upper housing 105 and lower housing 106 are held together by bolts115.

In order to install the device, workers must disassemble the entireapparatus and remove the gasket from the housing. Approximately half ofthe gasket is then forced over one end of one pipe. An end of the otherpipe is forced into the remaining portion of the gasket, thereby joiningthe two pipes together. To secure the pipes, the two halves of thehousing are placed around the gasket and then bolts or other fasteningdevices are used to complete the installation. In most cases, the innerdiameter of the gasket is slightly smaller than the outer diameter ofthe pipes. Therefore, the worker must stretch the gasket around the pipeends.

Another device for joining two pipes is described in U.S. Pat. No.7,401,819, herein incorporated in its entirety. The device described inU.S. Pat. No. 7,401,819 is a traditional coupling and a gasket that fitswithin the coupling. The gasket has a tongue that protrudes from theinner surface of the gasket. To join the pipes, one pipe is insertedinto the gasket up to the tongue and then the other pipe is insertedinto the other end of the gasket up to the tongue.

Each of these devices and methods takes time and can cause errors in thealignment and joining of the pipes. Therefore it is desirable to have acoupling that can be easily installed without disassembling prior touse.

SUMMARY

The present invention overcomes the problems and disadvantagesassociated with current strategies and designs and provides new toolsand methods of coupling pipes.

One embodiment of the invention is directed to a coupling for joiningtwo pipes. The coupling includes, an upper housing, a lower housing, atleast one fastening device for seeming the upper housing to the lowerhousing, and a gasket positioned within the upper and lower housings.The gasket is includes two primary seals, one on each outer edge of thegasket, and at least two secondary seals on a rib protruding from theinner surface of the gasket and between the two primary seals. Theprimary seals are adapted so that the gasket slides completely over theend of one pipe without disassembling the coupling.

In another embodiment, the fastening devices are selected from the groupincluding bolts, clips, snap-couplings, rivets, and ties. In certainembodiments, the inner diameter of the gasket is larger than the outerdiameter of the pipes. In certain embodiments, the outer diameter of thegasket is concave. In certain embodiments, each primary seal includes agripping extension. The gripping extension is adapted to grab the end ofa pipe as the gasket slides over the end of the pipe.

In certain embodiments, each primary seal has stepped ribs on the innersurface of the gasket. In certain embodiments, a portion of each of theupper housing and the lower housing is chamfered. The chamfered sectionsare on the inner surface of each of the upper housing and the lowerhousing adjacent to where the upper housing and the lower housing meet.

In certain embodiments, the coupling includes spacers to separate theupper housing from the lower housing. In certain embodiments, thespacers are removable. In certain embodiments, the spacers are permanentand compressible. In certain embodiments, the spacers are springs.

In certain embodiments, the primary seals have rounded interior ends. Incertain embodiments, the primary seals have interior ends that angletoward the outer surface of the gasket. In certain embodiments, thecorners of the outer surface of the gasket are concave. In certainembodiments, there are three secondary seals.

In certain embodiments, the coupling includes at least one slot in theouter surface of the gasket. In certain embodiments, there is onecontinuous slot around the circumference of the gasket. In certainembodiments, there are a plurality of slots around the circumference ofthe gasket. In certain embodiments, the coupling includes at least oneretaining device. In certain embodiments, the retaining device is asingle wire surrounding the upper housing and the lower housing. Incertain embodiments, the gasket is lubricated. In certain embodiments,the lower housing and the fastening device is one element attached tothe upper housing.

Another embodiment of the invention is directed toward a gasket. Thegasket includes two primary seals, one on each outer edge of the gasket,and at least two secondary seals on a rib protruding from an innersurface of the gasket and between the two primary seals. The primaryseals are adapted so that the gasket slides completely over the end of apipe without disassembling the coupling.

In certain embodiments, the inner diameter of the gasket is larger thanthe outer diameter of the pipe. In certain embodiments, the outerdiameter of the gasket is concave. In certain embodiments, each primaryseal includes a gripping extension. The gripping extension is adapted tograb the end of a pipe as the gasket slides over the end of the pipe. Incertain embodiments, each primary seal has stepped ribs on the innersurface of the gasket. In certain embodiments, the primary seals haverounded interior ends. In curtain embodiments, the primary seals haveinterior ends that angle toward the outer surface of the gasket. Incertain embodiments, the corners of the outer surface of the gasket areconcave.

In certain embodiments, there are three secondary seals. In certainembodiments, the gasket includes at least one slot in the outer surfaceof the gasket. In certain embodiments, there is one continuous slotaround the circumference of the gasket. In certain embodiments, thereare a plurality of slots around the circumference of the gasket.

Another embodiment of the invention is a method of coupling two pipes.The method includes, placing an assembled coupling over one end of onepipe, aligning a second pipe with the first pipe, sliding the couplingoff the end of the first pipe so that at least a portion of the couplingis around each pipe, and securing the coupling.

In certain embodiments, the coupling includes an upper housing, a lowerhousing, at least one fastening device coupling the upper housing to thelower housing, and a gasket positioned within the upper and lowerhousings. The gasket is comprised of two primary seals, one on eachouter edge of the gasket, and at least two secondary seals on a ribprotruding from an inner surface of the gasket and between the twoprimary seals. The primary seals are adapted so that the gasket slidescompletely over the end of the one.

In certain embodiments, the step of placing an assembled coupling overone end of a first pipe is completed without disassembling the coupling.In certain embodiments, the step of securing the coupling is completedby tightening the fastening devices. Certain embodiments further includethe step of aligning the coupling with a groove in each pipe. In anotherembodiment, the fastening devices are selected from the group includingof bolts, clips, snap-couplings, rivets, and ties. In certainembodiments, the inner diameter of the gasket is larger than the outerdiameter of the pipes. In certain embodiments, the outer diameter of thegasket is concave. In certain embodiments, each primary seal includes agripping extension. The gripping extension is adapted to grab the end ofa pipe as the gasket slides over the end of the pipe.

In certain embodiments, each primary seal has stepped ribs on the innersurface of the gasket. In certain embodiments, a portion of each of theupper housing and the lower housing is chamfered. The chamfered sectionsare on the inner surface of each of the upper housing and the lowerhousing adjacent to where the upper housing and the lower housing meet.

In certain embodiments, the coupling includes spacers to separate theupper housing from the lower housing. In certain embodiments, thespacers are removable. In certain embodiments, the spacers are permanentand compressible. In certain embodiments, the spacers are springs.

In certain embodiments, the primary seals have rounded interior ends. Incertain embodiments, the primary seals have interior ends that angletoward the outer surface of the gasket. In certain embodiments, thecorners of the outer surface of the gasket are concave. In certainembodiments, there are three secondary seals.

In certain embodiments, the coupling includes at least one slot in theouter surface of the gasket. In certain embodiments, there is onecontinuous slot around the circumference of the gasket. In certainembodiments, there are a plurality of slots around the circumference ofthe gasket. In certain embodiments, the coupling includes at least oneretaining device. In certain embodiments, the retaining device is asingle wire surrounding the upper housing and the lower housing. Incertain embodiments, the gasket is lubricated. In certain embodiments,the lower housing and the fastening device is one element attached tothe upper housing.

Other embodiments and advantages of the invention are set forth in partin the description, which follows, and in part, may be obvious from thisdescription, or may be learned from the practice of the invention.

DESCRIPTION OF THE DRAWINGS

The invention is described in greater detail by way of example only andwith reference to the attached drawings, in which:

FIG. 1 is a basic coupling device.

FIGS. 2a-c show the steps of installing a coupling of the instantinvention.

FIGS. 3a-c show a cut away view of FIGS. 2a -c.

FIG. 4 is a isometric view of an embodiment of a gasket of the instantinvention.

FIG. 5 is a cut away view of an embodiment of a gasket of the instantinvention.

FIGS. 6a-d are cut away views of another embodiment of a gasket of theinstant invention.

FIGS. 7a-b are cut away views of another embodiment of a gasket of theinstant invention.

FIG. 8 is a side view of an embodiment of the coupling of the instantinvention.

FIG. 9 is a side view of another embodiment of the coupling of theinstant invention.

FIG. 10 is a side view of another embodiment of the coupling of theinstant invention.

FIG. 11a-b are a cut away views of another embodiment of a gasket of theinstant invention.

FIG. 12 is a out away view of another embodiment of a gasket of theinstant invention.

FIG. 13 is a cut away view of another embodiment of a gasket of theinstant invention.

FIG. 14 is a cut away view of another embodiment of a gasket of theinstant invention.

FIGS. 15a-c are views of another embodiment of the coupling of thegasket of the instant invention.

FIG. 16 is a cut away view of a device for rolling a groove in a pipe.

FIG. 17 is a side view of another embodiment of the gasket.

DETAILED DESCRIPTION

As embodied and broadly described herein, the disclosures herein providedetailed embodiments of the invention. However, the disclosedembodiments are merely exemplary of the invention that may be embodiedin various and alternative forms. Therefore, there is no intent thatspecific structural and functional details should be limiting, butrather the intention is that they provide a basis for the claims and asa representative basis for teaching one skilled in the art to variouslyemploy the present invention.

A problem in the art capable of being solved by the embodiments of thepresent invention is quickly and easily joining two pipes togetherwithout first disassembling the coupling. It has been surprisinglydiscovered that certain configurations of the gasket allow joining twopipes together without having to disassemble the coupling. The gasketmay have certain elements that will be further described below thatallow it to slide completely over one pipe before the two pipes arejoined.

FIGS. 2a-2c show the steps of a method of installing an embodiment ofthe invention. In FIG. 2a , coupling 200 is placed completely over oneend of pipe 210. Coupling 200 remains held together by bolts 215 andsurrounds a gasket that is in contact with pipe 210. In FIG. 2b , pipe220 is brought into alignment with pipe 210 and an end of one pipe isplaced adjacent to an end of the other pipe. Preferably pipe 210 andpipe 220 are in direct contact with each other, however in certaincircumstances a slight gap is permissible. In the preferred embodiment,no part of the gasket protrudes between pipe 210 and 220, however, incertain embodiments, a portion of the gasket protrudes between pipe 210and 220. In FIG. 2c , coupling 280 is slid over the end of pipe 220 sothat a portion of coupling 200 surrounds pipe 210 and a portion ofcoupling 200 surround pipe 220. Preferably, coupling 205 is equallydistributed over pipe 210 and 220. Bolts 215 are then tightened to fullysecure coupling 200 over the two pipes and thus join the two pipes influid communication. The ends of each pine may have a groove 222 intowhich an inner diameter of coupling 200 fits upon completion of theassembly of coupling 200 and pipes 210 and 220, FIGS. 3a-3c show theabove described steps in a cut away, side view.

Bolts 215 may be of any material including but not limited to plastic,metal, fiber, and synthetic materials. Bolts 215 can be of anydimension. In certain embodiments, the heads of bolts 215 will break offat a predetermined torque to prevent over tightening of bolts 215. Inother embodiments bolts 215 may be replaced with other fasteningdevices. Any fastening device may be used, including clips,snap-couplings, rivets, and ties.

Pipes 210 and 220 can be used for transporting any material, including,but not limited to, water, oil, and gas. Pipes 210 and 220 may be of anysize and coupling 200 is of any complementary size to fit over and joinpipes 210 and 220. Preferably, pipes 210 and 220 are of the same size;however, in certain embodiments of coupling 200, pipes of differentsizes are joined.

FIG. 4 is an isometric view of an embodiment of a gasket 430 of theinvention. Gasket 430 can be made of any material that is capable offorming a seal and deforming. For instance, gasket 430 can be made fromEPDM, nitrile, fluro-elastomer, plastic, rubber, fiber, syntheticmaterials, resin, etc. Furthermore, gasket 430 may be produced usinginjection molding, extrusion, compression molding, machining, casting,3-D printing, or any other method known in the art. Gasket 430 ispreferably a continuous solid mass.

FIG. 5 is a cut away view of an embodiment of a gasket 530. Gasket 530preferably has an inner diameter that is larger than the outer diameterof the pipes around which gasket 530 is to be installed. Furthermore,the inner diameter of gasket 530 is preferably larger than the innerdiameter of a standard gasket. Such a configuration will assist in easeof installation of gasket 530. In certain embodiments, the outerdiameter of gasket 530 is also larger than the outer diameter of astandard gasket. Having a larger outer diameter assists in compressinggasket 530 into the pipes around which gasket 530 is installed.

Gasket 530, in certain embodiments, has a primary seal 535 on eitherside of gasket 530, which, upon complete assembly of the coupling, ispress into the outer walls of the pipes. In certain embodiments, gasket530 has an internal rib 540 positioned between the two primary seals535. Internal rib 540 includes at least two secondary seals 545 oneither end thereof. Secondary seals 545 are positioned so that uponcomplete assembly of the coupling each secondary seal 545 is pressedinto the outer walls of the pipes and is adjacent to the seam betweenthe two pipes. The positioning of primary seals 535 and secondary seals545 relative to the two pipes upon complete assembly of the coupling canbe seen more clearly in FIG. 3 c.

In certain embodiments, the outer diameter of gasket 530 is outwardlycurved or concave. The curve assists in compressing gasket 530 into thepipes and completing the seal between gasket 530 and the pipes uponcomplete assembly of the coupling. FIG. 17 shows another embodiment of agasket 1700 where at least a portion of the outer surface 1799 is flat.

FIGS. 6a-d show an embodiment of coupling 600 where primary seals 635contain extensions 636 to grip the edge of pipe 620. In certainembodiments, coupling 600 is held open by gasket 640 prior to insertionover pipe 620. See FIG. 6a . As coupling 600 and gasket 630 slide overpipe 620, extensions 636 of primary seal 635 grab the edge of pipe 620.See FIG. 6b . Upon further force, primary seal 635 will snap intoposition around pipe 620 as shown in FIG. 6c . Pipe 610 is then alignedwith pipe 620 and coupling 600 and gasket 630 are slid back off pipe 620and onto pipe 610 so that a portion of coupling 600 and gasket 630 arein contact with each pipe. Coupling 600 can then be tightened and engagea groove 612 and 622 at the end of each of pipe 610 and 620,respectively. See FIG. 6 d.

FIG. 7a shows an embodiment of a gasket 730. In gasket 730, primaryseals 735 have stepped ribs 737 on the inner surface of gasket 730. FIG.7b shows an enlarged view of the primary seal encircled in FIG. 7a . Itshould be noted that each primary seal is preferably a mirror image ofthe other primary seal, thus the discussion of the primary seal in FIG.7b applies to the other primary seal. While FIG. 7b shows two steppedribs 737, any number of stepped ribs may be included on primary seal735. In certain embodiments, each rib includes a first portion 737 athat is substantially parallel to the center line CL, shown in FIG. 7a ,and a second portion 737 b that is substantially perpendicular to firstportion 737 a. In other embodiments second portion 737 b is notsubstantially perpendicular to first portion 737 a but, instead, isoriented at an acute or obtuse angle to first portion 737 a Preferably,first portion 737 a is longer than second portion 737 b, however anyratio can be used.

FIG. 8 shows an embodiment of coupling 800. Coupling 800 consists of twohousings 805 and 806 held together by bolts 815. Both upper housing 805and lower housing 806 have inner portions 807 and 808, respectively,which are chamfered. Chamfered sections 807 and 808 consist of portionsof housings 805 and 806 that have been removed to widen the innerdiameter of the point of contact between the two housings. Chamferedsections 807 and 808 may be created by grinding, machining or meltingaway a portion of housings 805 and 806 or may be included during theproduction of housings 805 and 806. By adding chamfered sections 807 and808, pipe 820 can it through coupling 800 with housings 805 and 806 in acloser configuration than if chamfered sections 807 and 808 were notpresent. Thus, bolts 815 can be shorter.

FIG. 9 shows another embodiment of a coupling 900. Coupling 900 includesspacers 980 between upper housing 905 and lower housing 906. Spacers 980are placed adjacent to bolts 915 and keep upper housing 905 and lowerhousing 906 at a predetermined separation. The separation between upperhousing 905 and lower housing 906 helps in inserting a pipe intocoupling 900. Spacers 980 may be removable prior to tightening bolts915. In the removable embodiment, spacer 980 may be either disposable orreusable. In other embodiments, spacers 980 are permanent and compressupon tightening of bolts 915. The compressible embodiment may includescored sections to facility collapse. Although shown as rectangular,spacers 980 may be of any shape or size so long as spacers 980 keepupper housing 905 and lower housing 915 at a predetermined separation.Spacers 980 may be made of any material, including, but not limited to,metal, plastic, fiber, foam, natural materials, rubber, and silicone.

FIG. 10 shows an embodiment of the coupling 1000, similar to thecoupling 900 shown in FIG. 9. In coupling 1000, springs 1085 replacesspacers 980 of coupling 900. Springs 1085 are threaded over bolts 1015and be used to keep upper housing 1005 and lower housing 1006 separated.Springs 1085 compress when bolts 1015 are tightened, thereby eliminatingthe separation between upper housing 1005 and lower housing 1006.Springs 1085 may be of any material, including but not limited to metal,foam, and plastic.

FIG. 11a shows a cut away view of an embodiment of gasket 1130. Ingasket 1130, primary seals 1135 of gasket 1130 have rounded ends 1136.Rounded ends 1136 are located on the inside edge of primary seals 1135.Rounded ends 1136 may be of any radius and may be of any shape,including ovoid and circular. Rounded ends 1136 help gasket 1130 slideover a pipe. Alternatively, as shown in FIG. 12, ends 1236 are angledtoward the outer diameter of gasket 1230. Angle A may be of any anglegreater than zero. Additionally, in certain embodiments, gasket 1130 ofFIG. 11a , has the upper, outer corners 1132 removed or concave. Removedcorners 1132 may be of any shape or size. Removed corners 1132 assist inkeeping the upper and lower housings apart prior to tightening the boltsto further ease sliding the coupling over a pipe end. FIG. 11b showsanother embodiment of a gasket with rounded ends.

FIG. 13 shows a cut away view of an embodiment of gasket 1330. As in theembodiment of gasket 530 shown in FIG. 5, the embodiment of gasket 1330shown in FIG. 13 includes primary seals 1335 and internal rib 1340.However, in gasket 1330, internal rib 1340 includes three secondaryseals 1345. The middle secondary seal increases stiffness of internalrib 1340 and improves the seal between the pipes and gasket 1330.Additionally, the middle secondary seal may compensate for any errors inalignment of the pipes around which gasket 1330 is placed. The middlesecondary seal may be equal, larger, or smaller in size to the outersecondary seals.

FIG. 14 shows a cut away view of an embodiment of gasket 1430. Gasket1430 also includes primary seals 1435, internal rib 1440, and secondaryseals 1445. In certain embodiments of gasket 1430 there is at least oneslot 1490 in the outer diameter of gasket 1430. Preferably, slot 1490 islocated along the centerline of gasket 1430; however slot 1490 can be atany location. In certain embodiments of gasket 1430, slot 1490 iscontinuous around the entire diameter of gasket 1430. In otherembodiments of gasket 1430, slot 1490 is intermittent around thediameter of gasket 1430. Slot 1490 may be of any shape, including butnot limited to circular, ovoid, triangular, square, and rectangular. Inthe preferred embodiment, gasket 1430 will have one slot 1490; howeverany number of slots may be used. Slot 1490 lessens the amount ofmaterial used in gasket 1430 and provides extra free volume to preventover-compression of gasket 1430.

FIGS. 15a-15e show an embodiment of coupling 1500 that includes at leastone retainer 1586. Retainers 1586 may be made of any material, includingmetal, plastic, rubber, synthetic materials, and fibers. In certainembodiments of coupling 1500, the upper housing 1505 and lower housing1506 are adapted to hold retainers 1586 via notches 1587. Retainers 1586prevent upper housing 1505 and lower housing 1506 from separating duringinstallation of coupling 1500. Furthermore, retainers 1586 add stabilityand rigidity to coupling 1500 during installation and shipping.Retainers 1586 may be permanent or removable. In the removableembodiment, retainers 1586 may be disposable. While rectangularretainers 1586 are shown, any shape may be utilized. Furthermore,retainers 1586 may have any dimensions.

In certain embodiments, the pips ends are given a groove prior toassembly. Such grooves and a device to create such grooves can be foundin U.S. Pat. No. 6,196,039, herein incorporated in its entirety. FIG. 16shows an embodiment of a grove roller. Outside and inside rollers 1602,1604 are used to form an inward groove 1606 near an end 1616 of pipe1608. A peripheral surface of outside roller 1602 includes a firstprotrusion 1610 for creating groove 1606, and a second protrusion 1612,which is positioned closer to pipe end 1616 than protrusion 1610 whenforming groove 1606. A peripheral surface of inside roller 1604 includesa first indentation or grooving notch 1620 configured to receive firstprotrusion 1610, and which acts with first profusion 1610 of top roller1602 to form groove 1606. Inside roller also includes a secondindentation or notch 1622 configured to receive the second protrusion,and which provides space for pipe end 1616.

Second protrusion 1612 is configured to help increase the height of awall edge 1614 of groove 1606 and to resist flaring of pipe end 1616.Second protrusion 1612 includes a chamfered surface 1613 facing towardfirst protrusion 1610, and is rounded at the top and towards theopposite side.

Chamfered surface is at an angle β from a perpendicular to therotational axis of outside roller 1602, which can be in a range of about0° to about 70°.

When a radial load, L, is applied to outside roller 1602, it is believedthat protrusion 1612 applies a radial load, R, and an axial load, A, topipe and 1616. The axial load tends to push the pipe material towardprotrusion 1610; This action produces a higher groove edge wall 1614than typical with a conventional outside roller (e.g., an outside rollerwithout a protrusion 1612). Groove edge wall 1614 is formed with asubstantially vertical face 225, which intersects an adjacent arcuateportion 1630 having a tangent at an intersection angle d to the verticalface 1625. It is believed that protrusion 1612 with chamfered surface1613 tends to minimize intersection angle d, which helps to minimizeshearing of the groove wall. A small intersection angle d provides asteeper groove edge wall 1614. This is advantageous because it improvesthe attachment of the pipe to the coupling, increasing the pressurerating of the joint and the ability of the joint to resist bending.

The radial load R applied to pipe 1608 by protrusion 1612 also acts toresist flaring of pipe end 1616, tending to keep pipe end 1616 moreparallel with the central axis of pipe 1608. Reduced flaring isadvantageous because it improves the go sealing of a gasket against thepipe. Protrusion 1612 produces a small secondary groove 1638 having arounded profile.

Outside roller 1602 and inside roller 1604 each include a respectivealigning element configured to interact with the other aligning elementto align the outside and inside rollers when forming the groove. Outsideroller 1602 has an alignment bead 1615, which appears as a finger inprofile, and an alignment slot 1617. Inside roller 1604 includes acorresponding mating alignment slot 1619 which is configured to receivealignment bead 1615. Alignment slot 1619 is provided between facingwalls of inboard and outboard alignment beads 1621, 1623, which alsoappear as fingers in profile. Alignment slot 1617 of outside roller 1602is configured to receive alignment bead 1621. Alignment bead 1615 has adiameter which is less than the diameter of either protrusion 1610 orprotrusion 1612. Slot 1617 extends well into outside roller 1602.Outside roller 1602 tends to screw out when roll forming groove 1606 onpipe 1608. Therefore, an alignment surface 1626 on alignment bead 1615that faces protrusion 1610 contacts a second alignment surface 1628 onalignment bead 1621. This maintains alignment, of outride roller 1602with inside roller 1604.

In operation, pipe 1608 is positioned by the operator against a pipeabutment surface 1642 of protrusion 1621 of inside roller 1604. Outsideroller 1602 is brought down (arrow, L) by a manually operated hydraulicactuator (not shown) to form groove 1606. A pipe stand (not shown) canbe used to support pipe 1608 during groove rolling. Positioning rollersprovide an offset angle as described in Chatterley et al. U.S. Pat. No.5,570,603. Positioning the pipe with an offset ankle causes outsideroller 1602 to produce a torque which tends to draw pipe 1608 inwardbetween the rollers 1602, 1604, thus restricting pipe 1608 fromspiraling cut. Positioning rollers, along with the weight of pipe 1608,also act to resist a tendency of pipe 1608 to lift off the supportduring groove rolling.

In certain embodiments, the gasket is lubricated before assembly of thecoupling. Any lubrication can be used, including but not limited to,oils, fats, synthetic lubricants, and silicon oil. In other embodiments,the lubrication is applied to the pipes before insertion into thegasket.

In certain embodiments, the lower housing and bolts are replaced withone u-bolt that is secured to the upper housing at each end thereof. Theu-bolt can be made of any material including, plastic, metal, fiber, andsynthetic materials.

Other embodiments and uses of the invention will be apparent to thoseskilled in the art from consideration of the specification and practiceof the invention disclosed herein. All references cited herein,including all publications, U.S. and foreign patents and patentapplications, are specifically and entirely incorporated by reference.It is intended that the specification and examples be consideredexemplary only with the true scope and spirit of the invention indicatedby the following claims. Furthermore, the term “comprising of” includesthe terms “consisting of” and “consisting essentially of.”

The invention claimed is:
 1. A coupling for joining a first pipe and asecond pipe, the coupling comprising: an upper housing comprising afirst key at a first axial end configured to engage within a groove ofthe first pipe and a second key at a second axial end configured toengage within a groove of the second pipe; a lower housing comprising afirst key at a first axial end configured to engage within the groove ofthe first pipe and a second key at a second axial end configured toengage within the groove of the second pipe; at least one fasteningdevice coupling the upper housing to the lower housing; and a gasketpositioned within the upper and lower housings, the gasket including twoprimary seals, each primary seal formed on an outer edge of the gasket,and a rib protruding from an inner surface of the gasket and between thetwo primary seals, the rib defining a sealing surface contactable withan exterior surface of the first pipe when the first key of each of theupper housing and the lower housing is engaged within the groove of thefirst pipe and the second key of each of the upper housing and the lowerhousing is engaged within the groove of the second pipe, wherein thesealing surface defines a first axially outer edge and a second axiallyouter edge, wherein the rib further defines a cylindrical section facingradially inward, the cylindrical section being cylindrical when the atleast one fastening device is in an untightened condition, thecylindrical section defined between the first axially outer edge and thesecond axially outer edge, wherein the rib further comprises a secondaryseal, the secondary seal configured to contact the exterior surface ofthe first pipe and the exterior surface of the second pipe when thefirst pipe and the second pipe are joined end-to-end, the couplingadapted to slide over the first pipe such that the at least a portion ofthe first pipe extends axially beyond each outer edge of the gasketwhile the coupling remains in an assembled state, the coupling furtheradapted to join and seal the first pipe and the second pipe while thecoupling remains in an assembled state.
 2. The coupling of claim 1,wherein an innermost diameter of the gasket is larger than an outerdiameter of the first pipe and the second pipe when the at least onefastening device is in an untightened condition.
 3. The coupling ofclaim 1, wherein each primary seal includes a gripping extension.
 4. Thecoupling of claim 1, wherein each primary seal has a rounded interiorend.
 5. The coupling of claim 1, wherein the cylindrical section coversa seam defined between the first pipe and the second pipe when the firstpipe and the second pipe are joined end-to-end.
 6. The coupling of claim1, wherein an innermost diameter of the gasket is defined by thesecondary seal, and wherein an inner diameter of the cylindrical sectionis greater than the innermost diameter of the secondary seal.